You just HAVE to buy her a diamond, if you really love her.- since time immemorial, diamonds have been the ultimate expression of love.

Beauty, crafted by nature, diamonds are forever.

Diamonds are a girl's best friend.

Why? When most of us have no idea what carat means, why do Americans spend upwards of $10 billion annually on diamonds? Why are they a 'girl's best friend'? And if diamonds are so precious and valuable, why are they so difficult to re-sell?

Diamonds are indeed, forever.

In folklore, a diamond neutralizes poison, prevents nightmares and wards off insanity. Wards off insanity? You must be already insane to buy a diamond!

"Diamonds are forever" (Shirley Bassey, 1971)

Most diamonds are over a billion years old, and have been brought to us by volcanic eruptions from hundreds of miles beneath the earth's surface. Used for thousands of years as precious stones, but are they the most precious?

Hardly.

The idea that diamonds are rare and valuable is a relatively recent marketing idea by the diamond trade. In the past, diamonds were indeed relatively rare and found mainly in a few parts of Southern India and Brazil. But in 1870, new mines yielding tons of diamonds were opened in South Africa.

The notion that for centuries, men have given diamonds as symbols of marriage was a 'fact' created by copywriters of De Beers marketing department in the middle of the 20th century. They invented history by repeating the same message over and over again, and people believed it was true.

To protect their investment, financiers of mining operations created a tight cartel, regulating the production, pricing and marketing of the stones. But they have done more than just protect their commercial interests; through clever marketing, they have led us to believe that the diamond is a romantic token, that it represents love-eternal, and that the diamond is forever. So don't ever try to sell one, or you will break the love spell.

(If the unimaginable happened, where a sufficient number of people did realise they had been conned and started selling their diamonds, the price of diamonds would crash.)

After seeing diamonds worn by stars like Bette Davis, Marilyn Monroe and Elizabeth Taylor in romantic movies, people just had to own diamonds if they were to have any chance of being equally glamorous. They were, and still are, cleverly pushed through high-society magazines.

Even the British monarchy was fooled into sending Queen Elizabeth II to visit a diamond mine in South Africa, where she was presented with diamonds. All good PR orchestrated by the cartel.

Diamond Trilogy

Sales have been maintained, even through wartime and global recession, by perpetuating the luxurious must-have image.

More recently, to push sales further, the 'diamond trilogy' has hit the High Street. If you buy jewellery with three diamonds, you can enjoy love in three time dimensions: past love, present love and future love.

Just a minute... Past love!?

"With this ring I thee wed. It will always remind me of my previous girlfriend."

Three diamonds have no intrinsic value, unless perhaps if you are superstitious and believe in the power of playing cards (cartomancy), or if it's the card you need to win a game.

Mitsubishi

One notable winner of a diamond trilogy has been Mitsubishi.

These three congruent rhombi became the logo of the company some 130 years ago when founder Yataro Iwasaki chose the three-diamond mark as the emblem for his company. The mark is suggestive of the three-leaf crest of the Tosa Clan, Yataro's first employer, and also of the three stacked equilateral parallelograms of the Iwasaki kamon (family crest). From this logo comes the company name: mitsu (three) and hishi (water chestnut, also rhombus or diamond shape). Its worth is incalculable.

Although it's just nickels and dimes, the payout from a Triple Diamonds slot machine yields a better return than a trilogy diamond ring.

Another company, Alka-Seltzer, changed their TV commercials and the wording on packets in the 1960s directing people to take two pain relieving tablets instead of one. Since the company had determined that two tablets would relieve indigestion quicker than one, they could simply have just doubled the strength of each tablet. The decision was a marketing one and the tactic led to an almost doubling of sales.

So too with diamonds. A company could try to sell one large diamond rather than three small ones, but gone are the days of huge baubles; small is cute, and so we have the trilogy. Buy three and love will triple.

But there is no magical love element in a diamond. In reality, a diamond is just a carbon crystal that somebody has dug out of a dirty mine. In Africa especially, as shown by Leonardo DiCaprio in the movie Blood Diamonds, labour is cheap, working conditions unhealthy and dangerous, and the miners' homes are often far away.

Not only mining for diamonds, of course. Other highly-priced minerals, such as bauxite, cobalt, phosphate, platinum, tanzanite, vermiculite, zirconium, and of course gold, Africa's main mining resource.

Whilst mining camps do provide simple accommodation for the workers, no provision is made for their families. Consequently HIV from camp sex-workers is common. Even less glamorous are places like Surat in Gujarat, India, where 90% of all cut and polished diamonds are produced by child labourers.Or worse.De Beers, by far the most significant member of the cartel, is fully aware of this situation and has made great efforts to improve things recently.

And not before time. For decades, De Beers suffered a bad image for its price fixing and slave-labour production methods. But now they are gradually embracing CSR. In 2002 they introduced an employee health and wellness initiative and in 2003 they started a drug treatment programme. In 2004, they pleaded guilty to criminal price fixing and paid an $8.2m fine, and in 2005 signed an agreement with Attawapiskat First Nation people in Canada before mining on reservation land.

"Die Another Day" (Pierce Brosnan, 2002)

Neal Purvis and Robert Wade wrote the 2002 James Bond movie Die Another Day about trading 'conflict diamonds'

But the trade is still bad news for too many people. One problem with diamonds is their abundance, not scarcity. Traditionally, whenever a new source of diamonds is discovered (e.g. Russia, Australia, Canada), the cartel has been able to maintain control.

In the days of the British Empire, it was relatively easy to directly control places like Africa. But now these countries have their independence, the diamond companies have had to use careful and astute management to survive and prosper into the 21st century. And they have been helped to a large extent by the United Nations.

To stem the flow of funds to terrorist groups and politically-unstable central and Western African states, the U.N. Security Council has conveniently imposed a global ban on illicit trade in 'conflict diamonds' i.e. trade not controlled by the cartel,an initiative known as the Kimberley Process.

Fortunately, 'conflict diamonds' have almost disappeared now, due to the negative publicity, rigid controls, and the ending of the civil wars that raged across the African continent. Diamonds are still a major source of income for Mugabe's regime in Zimbabwe and the rapidly developing economies of places like China and India are pushing up demand for diamonds. So there is still pressure to get more rocks dug, polished and prepared by slave labour. The Kimberley Process may need to widen its scope from mining to processing.

But whether or not the diamonds in the High Street are cut and polished by a slave child or any other worker who is put at risk of contracting silicosis; whether or not the miner contracted TB (or HIV/AIDS, as explained above) from the poor working environment; and whether or not the proceeds will add to the coffers of terrorist organisations, people will still buy diamonds.

Because people believe the salesman's patter that diamonds are the best way of saying "I love you, forever."